Server system

ABSTRACT

A system includes a rack and one or more server systems mounted in the rack. A server system includes at least one sever node and each server node includes an array of devices including mass storage devices and at least one server device. Segments of the array of devices of a particular server node are mounted in sub-node chassis that include intra node connectors. Multiple sub-node chassis that each include devices such as mass storage devices or server devices of the sever node couple together via the intra node connectors when installed in a server system chassis to form a server node. Each server node of a server system may be a separate logical node. Also, the sub-node chassis of a server node may be configured for vertical airflow through the sub-node chassis in addition to cross airflow.

This application is a continuation of U.S. patent application Ser. No.15/087,746, filed Mar. 31, 2016, now U.S. Pat. No. 9,832,905, which ishereby incorporated by reference herein in its entirety.

BACKGROUND

Organizations such as on-line retailers, Internet service providers,search providers, financial institutions, universities, and othercomputing-intensive organizations often conduct computer operations fromlarge scale computing facilities. Such computing facilities house andaccommodate a large amount of server, network, and computer equipment toprocess, store, and exchange data as needed to carry out anorganization's operations. Typically, a computer room of a computingfacility includes many server racks. Each server rack, in turn, includesmany servers and associated computer equipment.

Computer systems typically include a number of components, suchcomponents include printed circuit boards, mass storage devices, powersupplies, and processors. Some known computer systems include aplurality of large, multiple-processor computers that are configuredinto rack-mounted components, and then are subsequently positionedwithin a rack system. Some known rack systems include 40 suchrack-mounted components and such rack systems will therefore generate asmuch as 10 kilowatts of waste heat. Moreover, some known data centersinclude a plurality of such rack systems.

Some computer systems are rack mounted servers that include a number ofhard disk drives (for example, eight or more hard disk drives) toprovide adequate data storage. Typically, the hard disk drives forservers are of a standard, off-the-shelf type. Standard, off-the-shelfhard disk drives are often a cost effective solution for storage needsbecause such hard disk drives can be obtained at relatively low cost.Nonetheless, in server designs using such standard hard disk drives, thearrangement of the hard disk drives may leave a substantial amount ofwasted space in a server chassis. This wasted space, especially whenmultiplied over many servers in a rack, may result in inadequatecomputing or storage capacity for a system.

Some servers that include a number of hard disk drives use a centralizedcontroller to control accesses to the hard disk drives, such as readsand writes. In such server designs using a centralized controller, afailure of the controller or ancillary equipment associated with thecontroller, may cause all the hard disk drives of the server to beunreachable. This reduces the reliability of the server.

Also some servers that include a number of hard disk drives may includea large number of hard disk drives mounted on a common chassis. Suchservers may be heavy, in some cases weighing 75 lbs. or more.Furthermore, rack systems in which such servers are to be mounted mayinclude elevated slots that require lifting the servers overhead or toother elevated positions. Lifting such heavy servers may be less thandesirable due to ergonomic risks and safety risks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a rack comprising multipleserver systems and an exploded view of a server node of one of theserver systems, according to some embodiments.

FIG. 2 is a front view of a server system chassis, according to someembodiments.

FIG. 3 is a side view of a sub-node chassis with devices mounted in thechassis, according to some embodiments.

FIG. 4 is a top view of a sub-node backplane, according to someembodiments.

FIG. 5 is a side view of a cutaway of a server system chassisillustrating multiple sub-node chassis coupled together and mounted inthe server system chassis, according to some embodiments.

FIG. 6 is a side view of a cutaway of a server system chassisillustrating multiple sub-node chassis coupled together and mounted inthe server system chassis, according to some embodiments.

FIG. 7 is a schematic top down view of a sub-node chassis that includesmass storage devices and a server device integrated into a sub-nodebackplane, according to some embodiments.

FIG. 8 is a schematic illustration of a server device configured tocouple with a sub-node backplane that occupies up to an equivalentvolume of space as a mass storage device, according to some embodiments.

FIG. 9A illustrates a side view of a sub-node chassis, according to someembodiments.

FIG. 9B illustrates a front view of multiple sub-node chassis coupledtogether via intra node connectors, according to some embodiments.

FIG. 9C illustrates a side view of a sub-node chassis, according to someembodiments.

FIG. 10 illustrates a method of installing a sub-node chassis in aserver system chassis mounted in a rack, according to some embodiments.

FIG. 11 illustrates a method of replacing a device mounted in a sub-nodechassis installed in a server system chassis, according to someembodiments.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the present invention as defined by the appendedclaims. The headings used herein are for organizational purposes onlyand are not meant to be used to limit the scope of the description orthe claims. As used throughout this application, the word “may” is usedin a permissive sense (i.e., meaning having the potential to), ratherthan the mandatory sense (i.e., meaning must). Similarly, the words“include,” “including,” and “includes” mean including, but not limitedto.

DETAILED DESCRIPTION OF EMBODIMENTS

Various embodiments of computer systems, and systems and methods forperforming computing operations, are disclosed. According to oneembodiment, a system includes a rack and a server system mounted in therack. The server system includes a server system chassis and multipleserver system nodes mounted in the server system chassis. Eachrespective server system node of the server system includes multiplesub-node chassis and an array of devices, wherein segments of the arrayof devices are mounted in respective ones of the multiple sub-nodechassis of the respective server node. Also, each of the respectiveserver system nodes includes at least one server device mounted in atleast one of the sub-node chassis of the respective server system node.Each sub-node chassis of each of the respective server system nodes isconfigured to be individually inserted into and removed from the serversystem chassis of the server system of which the server system node is apart. Also, each sub-node chassis includes an intra node connectorconfigured to couple with an intra node connector of an adjacentsub-node chassis to allow communications to and from mass storagedevices and server devices mounted in separate ones of the multiplesub-node chassis of the respective server node. For example, a serversystem may mount in one or more slots in a rack and include multipleserver nodes, the server nodes of the server system may be broken upinto segments mounted in separate sub-node chassis in order tofacilitate installation and removal of the server nodes into the serversystem chassis mounted in the rack. Breaking up the server node intomanageable segments may also enable the server node to be lifted by asingle person and installed in the rack by a single person. Also,continuing the example, the segments of the server node may function asa single node when installed in the server system when the segments ofthe server node are coupled together via intra node connectors.

According to one embodiment, a device includes a server node configuredto mount in a server system chassis. The server node includes multiplesub-node chassis and an array of devices, wherein segments of the arrayof devices of the server node are mounted in respective ones of themultiple sub-node chassis of the server node, wherein the array ofdevices includes mass storage devices. Each of the sub-node chassis areconfigured to be individually installed in the server system chassis.Also, each sub-node chassis includes an intra node connector configuredto couple with an intra node connector of an adjacent sub-node to allowcommunications to or from devices mounted in separate ones of themultiple sub-node chassis of the server node.

According to one embodiment, a method includes installing a sub-nodechassis in a server system chassis mounted in a rack, wherein thesub-node chassis comprises a portion of an array of mass storage devicesof the server node; installing an additional sub-node chassis in theserver system chassis mounted in the rack, wherein the additionalsub-node chassis comprises an additional portion of the array of massstorage devices of the server node; and causing an intra node connectorof the sub-node chassis to couple with a corresponding intra nodeconnector of the additional sub-node chassis to allow nodecommunications between the mass storage devices in the sub-node chassis.

As used herein, “backplane” means a plate or board to which otherelectronic components, such as mass storage devices, server devices,etc. can be mounted. In some embodiments, mass storage devices, whichcan include one or more hard disk drives, are plugged into a backplanein a generally perpendicular orientation relative to the face of thebackplane. In some embodiments, a server device is plugged into abackplane in a generally perpendicular orientation relative to the faceof the backplane. In some embodiments, a backplane includes one or morepower buses that can transmit power to components on the backplane, andone or more data buses that can transmit data to and from componentsinstalled on the backplane. In some embodiments, components thatcollectively function as a server device may be separately mounted on abackplane.

As used herein, a “cable” includes any cable, conduit, or line thatcarries one or more conductors and that is flexible over at least aportion of its length. A cable may include a connector portion, such asa plug, at one or more of its ends.

As used herein, “circuit board” means any board or plate that has one ormore electrical conductors transmitting power, data, or signals fromcomponents on or coupled to the circuit board to other components on theboard or to external components. In certain embodiments, a circuit boardis an epoxy glass board with one or more conductive layers therein. Acircuit board may, however, be made of any suitable combination ofmaterials.

As used herein, “chassis” means a structure or element that supportsanother element or to which other elements can be mounted. A chassis mayhave any shape or construction, including a frame, a sheet, a plate, abox, a channel, or a combination thereof. In one embodiment, a chassisis made from one or more sheet metal parts. A chassis for a computersystem may support circuit board assemblies, power supply units, datastorage devices, fans, cables, and other components of the computersystem.

As used herein, “computing” includes any operations that can beperformed by a computer, such as computation, data storage, dataretrieval, or communications.

As used herein, “data center” includes any facility or portion of afacility in which computer operations are carried out. A data center mayinclude servers dedicated to specific functions or serving multiplefunctions. Examples of computer operations include informationprocessing, communications, testing, simulations, power distribution andcontrol, and operational control.

As used herein, “mounting” a particular element on another elementrefers to positioning the particular element to be in physical contactwith the other element, such that the other element provides one or moreof structural support, positioning, structural load transfer,stabilization, shock absorption, some combination thereof, or the likewith regard to the particular element. The mounted particular elementmay be positioned to rest upon one or more upper surfaces of the otherelement, independent of coupling the elements via one or more couplingelements. In some embodiments, mounting the particular element toanother element includes coupling the elements such that the otherelement provides one or more of structural support, positioning,structural load transfer, stabilization, shock absorption, somecombination thereof, or the like with regard to the particular element.

As used herein, a “rack” means a rack, container, frame, or otherelement or combination of elements that can contain or physicallysupport one or more computer systems. In some embodiments a rack is astandard 19″ rack that conforms to electronic industries alliance (EIA)standards.

Some servers that mount in a rack may be general purpose servers, whilesome rack-mounted servers may be specially designed for storage capacityor compute capacity. Such specially designed servers may include storageservers that include several hard disk drives and controller serversthat include controllers that manage storage operations directed at thehard disk drives in the storage servers. A controller server may bemounted in a separate chassis in a separate rack slot from a rack slotin which a storage server is mounted. In such servers, some availablespace in the slot of the rack in which the controller server is mountedmay go unutilized, thus reducing the number and density of hard diskdrives and compute capacity that can be mounted in the rack. Forexample, only a portion of a space of a rack slot in which a controllerserver is mounted may be occupied by components of the controller serveror only a portion of an interior space within a chassis of a controllerserver may be occupied by components of the controller server. Also,some servers that include a separate controller server may be configuredsuch that the controller server and hard disk drives controlled by thecontroller server form a single logical node. In such servers, if acommon component fails, such as a component in the controller server,the whole logical node including all of the hard disk drives controlledby the controller server may become inaccessible. Thus in such designs alarge number of hard disk drives may be rendered unavailable due to asingle component failure.

In some embodiments, wasted space in a separate controller server may beeliminated by including a server device in a same chassis of a serversystem along with mass storage devices, such as hard disk drives, thatare controlled by the server device. Also, failure impact due to asingle component failure may be reduced by including several servernodes, that are each their own logical node and each with their ownserver device, in the same chassis of the server system. In someembodiments, a server system may include a server device mounted in asame chassis with mass storage devices, such as hard disk drives. Insome embodiments, the server device may occupy an equivalent volume ofspace in the chassis as one of the mass storage devices. In someembodiments, the server device may be integrated into a backplane of theserver node. Thus a greater density of mass storage devices per rack maybe achieved by eliminating unutilized space of a separate controllerserver. Also, in some embodiments, multiple server nodes each comprisingits own server device and an array of mass storage devices controlled bythe server device may be included in a chassis of a server system. Themultiple server nodes may be independent of each other, so that if acomponent in one server node fails, such as a server device of theserver node, the other server nodes in the server system may not beaffected by the failure and continue to be available to perform storageoperations.

Furthermore, a server node of a server system may include an array ofdevices comprising mass storage devices and at least one server device,wherein segments of the array of devices are mounted in separatesub-node chassis that can be installed in the server system chassisseparately. The sub-node chassis of a server node may be coupledtogether when installed in the server system chassis to form a logicalnode or server node of the server system. In some embodiments, a serversystem may include multiple such server nodes, wherein each server nodecomprises multiple sub-node chassis comprising mass storage devices andat least one server device that are coupled together to form a logicalnode or server node of the server system.

In some embodiments, a server system chassis may be a single chassisthat is configured to mount in a rack and configured to mount multiplesets of sub-node chassis. For example, a server system chassis mayoccupy one or more slots in a rack. In some embodiments, a height of aserver system may span multiple 1 U slots in a standard 19″ EIA rack.For example, a server system may have a height of 1 U, 2 U, 3 U, 4 U, 5U, 1.5 U, 2.5 U, etc.

FIG. 1 is a perspective view illustrating a rack comprising multipleserver systems and an exploded view of a server node of one of theserver systems, according to some embodiments.

System 100 includes rack 102 and server systems 104, 106, and 108mounted in rack 102. Each of server systems 104, 106, and 108 includemultiple server nodes. Each server node includes mass storage devicesand at least one server device that together form a separate logicalnode of the server system. For example, server system 104 includesserver nodes 110, 112, and 114, wherein each server node includes anarray of mass storage devices and at least one server device forcontrolling storage operations directed at the array of mass storagedevices and/or for performing compute operations.

In some embodiments, a server node of a server system may comprisemultiple sub-node chassis coupled together via intra node connectors,wherein each sub-node chassis comprises a segment of an array of massstorage devices and server devices of the server node. FIG. 1illustrates an exploded view of server node 110. Server node 110includes sub-node chassis 116, 118, 120, and 122. Devices 124 aremounted in sub-node chassis 116, 118, 120, and 122. In some embodiments,devices 124 may be mass storage devices, such as hard disk drives. Insome embodiments, devices 124 may be server devices. In someembodiments, devices 124 mounted in one of sub-node chassis 116, 118,120, or 122 may include a combination of mass storage devices and serverdevices. For example device 126 mounted in sub-node chassis 122 is aserver device 126 for server node 110, whereas the other ones of devices124 mounted in sub-node chassis 122 are mass storage devices 128.

In some embodiments, components that function as a server device may bemounted on a backplane included in at least one sub-node chassis of aset of sub-node chassis that couple together to form a server node. Insome embodiments, a server device may be a separate device that plugsinto a connector on a backplane included in a sub-node chassis.

In some embodiments, a server device that is a separate device thatplugs into a backplane, such as server device 126, may occupy up to anequivalent volume of space within sub-node chassis 122 as one of themass storage devices mounted in sub-node chassis 122, such as one ofmass storage devices 128. In some embodiments, a server device, such asserver device 126, may have a form factor that is equivalent to a formfactor of a mass storage device, such as one of mass storage devices128. In some embodiments, a server device, such as server device 126,may have a form factor that is smaller than a form factor of a massstorage device, such as one of mass storage devices 128. For example,server device 126 may have a form factor such that server device 126 canfit within a space that has a volume equivalent to a volume of a massstorage device, such as one of mass storage devices 128.

A server device, such as server device 126, may include one or morenetwork ports and be configured to communicate with systems outside ofsystem 100. For example, server device 126 may be configured to receiveread and write requests from other computing systems and/or servers toread data from and write data to mass storage devices 128 or other massstorage devices in any of sub-node chassis 116, 118, 120, or 122.

In some embodiments, a server node in a server system that forms its ownlogical node, such as one of server nodes 110, 112, or 114 in serversystem 104, may include more than one server device in the server node.For example, a server node, such as one of server nodes 110, 112, or114, may include multiple server devices in the same array of devicesthat forms the server node. The multiple server devices of a server nodemay be configured to coordinate with each other to control storageoperations related to mass storage devices of the server node, such asmass storage devices 124 and to perform compute operations. In someembodiments, a ratio of server devices to mass storage devices may beadjusted by adding or removing mass storage devices and/or serverdevices from sub-node chassis that forms the server node.

In some embodiments, multiple server devices may be included in a singleserver node to provide additional computing capacity for the servernode.

In some embodiments, mass storage devices and/or a server device of aserver node are configured to be removed from the server node whileother server nodes of the server system are in operation. For example,segments of server node 110 in sub-node chassis 116, 118, 120 and 122may be removed from server system 104 while server nodes 112 and 114remain in operation.

In some embodiments, data storage operations for mass storage devices ofa server node, such as one of server nodes 110, 112, or 114, may becontrolled by a server device included in the server node without usingan additional controller. For example, the mass storage devices of aserver node may be controlled without an external controller controllingstorage operations of the mass storage devices of the server node. Forexample each of server nodes 110, 112, or 114 may include their ownserver device and not rely on an external controller mounted in anotherrack slot in rack 102 to control data operations of mass storage devicesin respective ones of server nodes 110, 112, or 114.

By including server devices in an array with mass storage devices in asingle chassis, a high density of mass storage devices in a rack can beachieved. For example, in some embodiments, a 48 U standard 19″ rack mayinclude over a thousand 3.5″ hard disk drives along with server devicesfor controlling the hard disk drives, wherein the hard disk drives aremounted in sub-node chassis included in multiple server systems mountedin the rack. In some embodiments, a 48 U standard 19″ rack may includemore or less hard disk drives mounted in sub-node chassis thanillustrated in FIG. 1. In some embodiments, other rack sizes may beused.

Furthermore, a server node of a server system that includes mass storagedevices and server devices mounted in sub-node chassis may be configuredsuch that a single person can install respective sub-node chassisincluding devices such as mass storage devices and server devicesmounted in the sub-node chassis of a server node. For example, somepeople may not be able to lift server nodes into a rack that weigh overa certain amount, for example more than 50 lbs. However, the same personmay be able to lift segments of a server node that each weigh less than50 lbs. For example, server node 110 is illustrated in FIG. 1 to includefour segments each mounted in its own sub-node chassis, so that while aperson may not be able to lift all the mass storage devices and serverdevices of server node 110 at one time, the same person may be able tolift sub-node chassis 116 including devices 124 mounted in sub-nodechassis 116 into server system chassis 130, and then subsequently liftsub-node chassis 118 including devices 124 mounted in sub-node chassis118, and repeat the same process for sub-node chassis 120 and 122.

In some embodiments, a sub-node chassis, such as any of sub-node chassis116, 118, 120, or 122, may be configured to couple with a cover thatincludes rail guides configured to slide on rails of a server systemchassis. For example, cover 134 includes rail guides 132 that areconfigured to slide on rails 142 of server system chassis 130. In someembodiments, each sub-node chassis of a server node may couple with acover that includes rail guides that extend away from the cover by adifferent distance than rail guides of another cover of an adjacentsub-node chassis. For example, rail guides 132 of cover 134 may extend adistance from cover 134 that is greater than a distance from cover 136that rail guides 132 of cover 136 extend. Each subsequent sub-nodechassis cover of a server node may include rail guides that extend awayfrom its respective cover by an incrementally shorter or longerdistance. Thus, when installed on a common rail in a server systemchassis, a set of sub-node chassis with respective covers may bepositioned at different elevations in the server system chassis. In someembodiments, a set of sub-node chassis of a server node may bepositioned in a stair step arrangement such that an air space above theset of sub-node chassis increases and an air space below the sub-nodechassis decreases from one sub-node chassis to the next sub-node chassiswhen the set of sub-node chassis of the server node are installed on oneor more rails of a server system chassis in the stair-step arrangement.

In some embodiments, a sub-node chassis may include an intra nodeconnector coupled to the sub-node chassis that is configured to couplewith an intra node connector of an adjacent sub-node chassis when thesub-node chassis and the adjacent sub-node chassis are installed in aserver system chassis. For example, sub-node chassis 116 includes intranode connector 144 coupled to sub-node chassis 116. In some embodiments,a sub-node chassis may include multiple intra node connectors coupled tothe sub-node chassis at different elevations. For example, sub-nodechassis 118 includes intra node connector 146 at a same elevation asintra node connector 144 (hidden behind the sub-node chassis) ofsub-node chassis 116 and also includes intra node connector 148 at alower elevation on sub-node chassis 118 than intra node connector 146. Asub-node chassis that includes intra node connectors mounted atdifferent elevations on the sub-node chassis may be configured to couplewith sub-node chassis of a set of sub-node chassis that are arranged ina stair step arrangement such that a first adjacent sub-node chassis isat a higher elevation than the sub-node chassis and couples with thehigher elevation intra node connector and another adjacent sub-nodechassis on an other side of the sub-node chassis is at a lower elevationthan the sub-node chassis and couples with the lower intra nodeconnector. In some embodiments, an edge of a backplane may be configuredto couple with a connector of an adjacent sub-node chassis as an intranode connector.

In some embodiments, an array of devices of a server node may be brokeninto segments, where each segment is mounted in a sub-node chassis in avariety of other configurations. For example, a segment may include moreor less devices of a server node. Also, in some embodiments, segments ofa server node may be mounted in sub-node chassis that couple together onother sides of the sub-node chassis than as illustrated in FIG. 1.

In some embodiments, a server system chassis, such as server systemchassis 130, may include multiple sets of rails for mounting multiplesets of sub-node chassis of multiple server nodes in the server systemchassis.

FIG. 2 is a front view of a server system chassis, according to someembodiments. System 200 illustrated in FIG. 2 may be a top portion ofsystem 100 illustrated in FIG. 1 and server system chassis 130 asillustrated in FIG. 1 may be a server system chassis 202 as illustratedin FIG. 2. System 200 includes rack 204 and server system chassis 202mounted on shelf 206 of rack 204. In some embodiments, a server systemchassis may be mounted in a rack via other suitable means, such as siderails, without using a shelf, such as shelf 206. Server system chassis202 includes rails 208 for mounting sub-node chassis of a first severnode in server system chassis 202, rails 210 for mounting sub-nodechassis of an additional server node in server system chassis 202, andrails 212 for mounting sub-node chassis of another server node in serversystem chassis 202. In some embodiments, a server system chassis mayinclude any number of rails for mounting any number of server nodes in aserver system chassis. In some embodiments, a single rail may beconfigured for mounting a sub-node chassis of a server node in a serversystem chassis. In some embodiments, other suitable rail designs may beused in addition to the rail designs illustrated in FIG. 2.

In some embodiments, a server system or rack may include one or more airmoving devices, such as fans that cause air to flow over devices mountedin a server system.

FIG. 3 is a side view of a sub-node chassis with devices mounted in thechassis, according to some embodiments. Segment 300 may be any of thesegments of server nodes 110, 112, 114, such as any of sub-node chassis116, 118, 120, or 122 illustrated in FIG. 1. Segment 300 includessub-node chassis 302 and cover 304 coupled to sub-node chassis 302 viapins 306 and 308. In some embodiments, other suitable mechanisms may beused to couple a cover to a sub-node chassis, such as screws, latches,clasps, etc. Cover 304 includes rail guides 310. In some embodiments,rail guides may run along a length of a cover, such as rail guides 310illustrated in FIG. 3. In some embodiments, a rail guide may only runalong a portion of a cover. For example, in some embodiments portions ofrail guides 310 may be mounted on corners of cover 304 and a centerportion above cover 304 may not include rail guides. In someembodiments, rail guides, such as rail guides 304 may includeventilation holes in the rail guides to allow air to flow around andthrough the rail guides.

Sub-node chassis 302 includes devices 312 and 314 mounted in sub-nodechassis 302. In some embodiments, devices 312 and 314 may be massstorage devices, server devices, or some combination of mass storagedevices and server devices. Sub-node chassis 302 also includes intranode connector 316 that is mounted at a higher elevation on sub-nodechassis 302 than intra node connector 318 which is mounted at a lowerelevation on sub-node chassis 318. In addition, sub-node chassis 302includes backplane 320 mounted on a bottom side of sub-node chassis 302.In some embodiments an intra node connector, such as intra nodeconnector 316, may be mounted on a top side of a backplane, such asbackplane 320, and another intra node connector, such as intra nodeconnector 218, may be mounted on a bottom side of a backplane, such as abottom side of backplane 320. In some embodiments, an intra nodeconnector may be an edge of a backplane that is configured to coupleinto an intra node connector included in an adjacent sub-node chassis.For example, intra-node connector 316 or intra-node connector 318 may bean edge of backplane 320 that is configured to couple with an intra nodeconnector of an adjacent sub-node chassis.

In some embodiments, a sub-node chassis may include open corners thatallow a bottom side of devices mounted in the chassis to be accessed viathe open corner. For example, in order to remove device 312 fromsub-node chassis 302, a person may apply a force to bottom side ofdevice 312 which is accessible via open corner 324. In some embodiments,mass storage devices or server devices such as devices 312 and 314 maybe coupled to backplane 320 via connectors, and applying a force to abottom side of one of devices 312 or 314 may cause the device todisconnect from the connector of the backplane. In some embodiments, asub-node chassis may include angled support members, such as angledsupport member 322, that provide rigidity to the sub-node chassis andalso allows access to devices, such as devices 312 and 314, via opencorners, such as open corner 324.

In some embodiments, a backplane mounted in a sub-node chassis mayinclude openings that permit air to flow through the backplane andacross devices mounted in the sub-node chassis.

FIG. 4 is a top view of a sub-node backplane, according to someembodiments. Backplane 400 illustrated in FIG. 4 may be a backplaneincluded in any of the sub-node chassis described in FIGS. 1-3 and FIGS.5-11. Backplane 400 includes intra node connector 402 mounted on a topside of backplane 400 and intra node connector 404 mounted on a bottomside of backplane 400. Device connectors 406 are mounted in two rows ofthree each and are configured to couple mass storage devices and serverdevices to backplane 400. In some embodiments, a backplane, such asbackplane 400, may include more or less device connectors, and thedevice connectors may be arranged in several different arrangements,such as more or less columns and more or less rows. In some embodiments,an intra node connector, such as intra node connector 402 or intra nodeconnector 404, may be an edge of a backplane, such as an edge ofbackplane 400, that includes contacts configured to couple with an intranode connector of an adjacent sub-node chassis to allow communicationsand/or power to flow between components of the adjacent sub-node chassiswhen coupled together.

In some embodiments, a sub-node backplane, such as backplane 400 mayinclude openings, such as openings 408, configured to allow air to flowthrough the backplane and across devices coupled to the backplane. Forexample, backplane 400 includes respective ones of openings 408 betweenrespective device connectors 406.

In some embodiments, a sub-node backplane may be configured with opencorners to allow access to remove devices mounted on the backplane viathe open corners. For example, backplane 400 includes open corners 410,412, 414, and 416. In some embodiments, a sub-node backplane, such asbackplane 400 may be recessed at locations on the backplane thatcorrespond with corners of devices, when the devices are mounted on thebackplane. This may allow the devices to be easily removed from thebackplane by accessing a bottom side of the device at the open corner.For example, backplane 400 is recessed at open corners 410, 412, 414,and 416.

In some embodiments, multiple sub-node chassis of a server node may bepositioned in a server system chassis to form a cold air plenum and ahot air plenum. The cold air plenum may receive air from a cold aisleand air that has passed over devices mounted in the sub-node chassis ofthe server node may flow into a hot air plenum that exhausts hot airinto a hot aisle. A server system chassis, rack, or structure coupled toa rack or server system chassis may include one or more air movingdevices, such as fans that cause air to flow through a server systemchassis. In some embodiments, multiple sub-node chassis of a server nodemay be arranged in a server system chassis such that a cross sectionalarea of a cold plenum decreases from sub-node to sub-node across theserver node and such that a cross sectional area of a hot plenumincreases from sub-node to sub-node across the server node.

FIG. 5 is a side view of a cutaway of a server system chassisillustrating multiple sub-node chassis coupled together and mounted inthe server system chassis, according to some embodiments. Server system500 includes cold plenum 502 below multiple sub-node chassis 506 of aserver node and hot plenum above multiple sub-node chassis 506 of aserver node. Rail guides 508 of covers 514 of sub-node chassis 506couple with rail 510 of server system chassis 512. Each rail guide 508of covers 514 coupled with sub-node chassis 506 extends away aparticular distance from respective ones of covers 514. In someembodiments, rail guides of covers for adjacent sub-node chassis of aserver node may extend away from the covers of the respective sub-nodechasses by incrementally increasing or decreasing distances. Forexample, rail guides 508 extend away from covers 514 by incrementallygreater distances for each respective sub-node chassis 506. This causescold air plenum 502 to reduce in cross-sectional area and hot air plenum504 to increase in cross-section area. Air that is pulled into serversystem chassis 512 from cold aisle 516 enters cold air plenum 502 and ascold air plenum 502 reduces in cross sectional area, a portion of theair in cold air plenum 502 flows through openings in backplanes includedin respective ones of the multiple sub-node chassis 506 and passesacross devices such as mass storage devices and server devices mountedin respective ones of sub-node chassis 506. Heated air that has removedwaste heat from devices mounted in respective ones of sub-node chassis506 then flows into hot air plenum 504 and is exhausted out of serversystem chassis 512 and into hot aisle 518.

In some embodiments, other arrangements may be used to position sub-nodechassis in a server system chassis such that the multiple sub-nodechassis of a server node form a cold air plenum and a hot air plenumabove or below the sub-node chassis. Also, other arrangements may beused to cause elevations of sub-node chassis to change across a servernode. For example, in some embodiments, a sub-node chassis may includelegs and feet that position the sub-node chassis at different elevationsin a server system chassis.

FIG. 6 is a side view of a cutaway of a server system chassisillustrating multiple sub-node chassis coupled together and mounted inthe server system chassis, according to some embodiments. For example,server system chassis 602 includes multiple sub-node chassis 604 thateach include legs 606 and feet 608. In some embodiments, respectivesub-node chassis of a server node may have respectively shorter legs,such that the sub-node chassis when installed in a server system chassisform a cold plenum with a reducing cross sectional area and a hot plenumwith an increasing cross sectional area. For example, server systemchassis 602 includes cold air plenum 610 below multiple sub-node chassis604 and hot air plenum 612 above multiple sub-node chassis 604. In someembodiments, legs of a sub-node chassis may include openings, such asopenings 614 that allow air to flow through the legs of the sub-nodechassis.

In some embodiments, a server device may be integrated into a backplaneof at least on sub-node chassis of a server system, as described belowin regard to FIG. 7. In some embodiments, a server device may be aseparate device that couples with a backplane, as described in moredetail below in regard to FIG. 8. FIG. 7 is a schematic top down view ofa sub-node chassis that includes mass storage devices and a serverdevice integrated into a sub-node backplane, according to someembodiments.

Sub-node backplane 700 includes mass storage devices 702, 704, 706, 708,and 710 coupled to sub-node backplane 700 via device connectors, similarto the device connectors described in regard to FIG. 4. Sub-nodebackplane 700 also include an intra node connector 712 mounted on abottom side of the sub-node backplane. In some embodiments, an intranode connector could be mounted on a top side of sub-node backplane 700.Sub-node backplane 700 also includes processor 714, memory 716, networkinterface card 718, management and control circuit 720, power connector722, and network port 724 coupled to sub-node backplane 700. Processor714 comprises a processor and interface for communicating with massstorage devices via sub-node backplane 700. Processor 714 also comprisesa communication interface with memory 716, mass storage devices 702,704, 706, 708, 710, and intra node connector 712. In some embodimentsprocessor 714 may be a system on a chip (SoC), a general purposeprocessor, an application specific integrated circuit (ASIC), or anotherdevice that provides processing capability and communicates with viasub-node backplane 700 and intra node connector 712. In someembodiments, management and control circuit 720 manages conditions of aserver node of which sub-node backplane 700 is a part such astemperature conditions. In some embodiments, management and controlcircuit 720 includes an interface for connecting with an external heathmonitoring system, such as an intelligent platform management interface(IPMI). In some embodiments, memory 716 are RAM devices such as doubledata rate fourth generation synchronous dynamic random-access memory(DDR4) or other suitable RAM devices. In some embodiments, network port724 is a small form factor pluggable 10 gigabit port or other suitableport for network connection. In some embodiments, power connector 722may be configured to receive electrical power via a cable connection. Insome embodiments, sub-node backplane 700 may include a boot drive thatstores program instructions for booting a server node of which sub-nodebackplane 700 is a part. In some embodiments, boot instructions may bestored in a remote location. In some embodiments connectors that coupledevices such as devices 702, 704, 706, 708, and 710 to sub-nodebackplane 700 may be mini SAS HD connectors. In some embodiments,communication via connectors may be in accordance with a FibreChannelstandard, Serial ATA standard, or other suitable standard. In someembodiments, a backplane may couple with connectors to directly coupleserver devices with mass storage devices via a backplane without usingexpanders or host bus adapters.

FIG. 8 illustrates a server device that is separate from a backplane andthat occupies up to an equivalent volume of space in a sub-node chassisas a mass storage device, according to some embodiments. Server device800 illustrated in FIG. 8 may be any of the server devices described inFIGS. 1-7 and 9-10. In some embodiments, server device 800 may have aform factor that occupies up to an equivalent volume of space as a massstorage device, such as a 3.5″ hard disk drive.

Server device 800 includes system on a chip 802, memory devices 810,power connector 808, network interface controller 804, network port 806,management and control circuit 812, boot drive 814, and connectors 816and 818. System on a chip 802 comprises a processor and interface forcommunicating with mass storage devices via connectors 816 and 818.System on a chip 802 also comprises a communication interface withmemory 810. In some embodiments system on a chip 802 may be an SoC, ageneral purpose processor, an application specific integrated circuit(ASIC), or another device that provides processing capability andcommunicates with connectors 816 and 818. In some embodiments,management and control circuit 812 manages conditions of server device800 such as temperature conditions. In some embodiments, management andcontrol circuit 812 includes an interface for connecting with anexternal heath monitoring system, such as an intelligent platformmanagement interface (IPMI). In some embodiments, memory devices 810 areRAM devices such as double data rate fourth generation synchronousdynamic random-access memory (DDR4) or other suitable RAM devices. Insome embodiments, network port 806 is a small form factor pluggable 10gigabit port or other suitable port for network connection. In someembodiments, power connector 808 may be configured to receive electricalpower via a cable connection, and in some embodiments, power connector808 may be configured to couple with a backplane and receive electricalpower via the backplane. In some embodiments, boot drive 814 is a solidstate drive that stores program instructions for booting server device800. In some embodiments, boot instructions for server device 800 may bestored in a remote location and boot drive 814 may be omitted. In someembodiments connectors 816 and 818 are mini SAS HD connectors. In someembodiments, other suitable connectors may be used for connectors 816and 818. In some embodiments, communication via connectors 816 and 818may be in accordance with a FibreChannel standard, Serial ATA standard,or other suitable standard. In some embodiments, a backplane may couplewith connectors 816 and 818 to directly couple server device 800 withmass storage devices via a backplane without using expanders or host busadapters to connect server device 800 to mass storage devices.

In some embodiments, a server device, such as server device 800 may bemounted in a sub-node chassis via connectors 816 and 818 oriented downtowards a bottom of a slot in the sub-node chassis and coupled with abackplane that runs beneath mass storage devices mounted in the sub-nodechassis and the server device mounted in the sub-node chassis. In someembodiments, a server device, such as server device 800 may be coupledto backplanes via cables connected to connectors 816 and 818.

In some embodiments, a server device such as server device 800 may beintegrated into a backplane as discussed in regard to FIG. 7. Forexample the respective components of server device 800 described abovemay be mounted on a circuit board of a backplane.

In some embodiments, a server device, such as server device 800, mayhave a form factor that is equivalent to a form factor of a standard3.5″ hard disk drive. In some embodiments a server device, such asserver device 800, may have a different form factor.

In some embodiments, an array of devices of a server node may besegmented into segments that run from front to back of a server systemchassis. Each segment may include a sub-node chassis that extends from afront of a server system to a back of a server system when installed ina server system chassis of the server system. In some embodiments, asub-node chassis of a server node may include intra node connectorsmounted on a side of the sub-node chassis that are configured to couplewith a corresponding intra node connector on a side of an adjacentsub-node chassis. In some embodiments, a sub-node chassis may includemultiple backplanes that are mounted in the sub-node chassis atdifferent elevations, so that when the sub-node chassis is installed ina server system, the multiple backplanes and devices, such as massstorage devices and server devices, mounted on the multiple backplanesare at different elevations in a server system chassis when the sub-nodechassis is installed in the server system chassis.

For example, FIGS. 9A, 9B, and 9C illustrate embodiments of sub-nodechassis that include backplanes at different elevations within thesub-node chassis. In some embodiments, a sub-node chassis, such as thoseillustrated in FIGS. 9A-C may run front to back when installed in aserver system chassis.

Segment 900 includes sub-node chassis 902 and devices 904 mounted insub-node chassis 902. Devices 902 may include mass storage devices andone or more server devices. Backplanes are positioned at differentelevations within sub-node chassis 902 and are coupled together viaconnectors 908. Cover 910 is coupled to sub-node chassis 902 andincludes rail guides configured to slide on rails of a server systemchassis. In some embodiments, a sub-node chassis, such as sub-nodechassis 902, may include legs as described in regard to FIG. 6 and mayinclude open corners as described in FIGS. 3-4. In addition, a sub-nodechassis, such as sub-node chassis 902 may form a cold air plenum and ahot air plenum when installed in a server system chassis in a similarmanner as described in FIGS. 5 and 6.

FIG. 9B illustrates a front view of multiple sub-node chassis coupledtogether via intra node connectors, according to some embodiments. Anyof sub-node chassis 912 illustrated in FIG. 9B may be a sub-node chassis902 as illustrated in FIG. 9A. Each sub-node chassis 902 includes railguides 914 and are configured to be individually mounted in a serversystem chassis and subsequently coupled together to form a server nodeof the server system. For example, intra node connectors 916 betweenadjacent ones of sub-node chassis 912 may couple together to allowcommunications between devices mounted in different ones of sub-nodechassis 912. In some embodiments a server node comprising multiplesub-node chassis, such as multiple ones of sub-node chassis 912, mayinclude a single server device or may include multiple server devices inone or more of the sub-node chassis coupled together to form the servernode.

In some embodiments, a sub-node chassis such as sub-node chassis 902illustrated in FIG. 9A may include a bottom surface 918 as illustratedin FIG. 9C and may include an air plenum, such as air plenum 920, withinthe sub-node chassis between the bottom surface, such as bottom surface918, and the backplanes, such as backplanes 906. In some embodiments,cover 910 and/or rail guides may be omitted. For example, a sub-nodechassis may have a tub configuration that slides on a server systemchassis via a bottom surface of the sub-node chassis and may includedevices mounted in the chassis at different elevations above the bottomsurface of the of the sub-node chassis wherein a space between thebottom surface of the sub-node chassis and the different backplanesmounted within the sub-node chassis forms a cold air plenum or a hot-airplenum without being supported in a server system chassis by rail guidesor legs.

FIG. 10 illustrates a method of installing a sub-node chassis in aserver system chassis mounted in a rack, according to some embodiments.At 1002, a sub-node chassis of a server node is installed in a serversystem chassis. In some embodiments, a sub-node chassis may include acover coupled to the sub-node chassis wherein the cover includes railguides. The rail guides may be configured to slide on one or more railsmounted in a server system chassis. In some embodiments, a server systemchassis may include a separate set of one or more rails for each servernode that is to be mounted in the server system chassis. A sub-nodechassis may be any of the sub-node chassis described in FIGS. 1-9.

At 1004, an additional sub-node chassis of the server node is installedin the server system chassis. In some embodiments, the additionalsub-node chassis may be installed on a same rail as the sub-node chassisinstalled at 1002. The additional sub-node chassis may include a covercoupled to the sub-node chassis that includes rail guides configured toslide on one or more rails mounted in the server system chassis. In someembodiments, the rail guides of the cover coupled to the additionalsub-node chassis may extend away from the sub-node chassis a greater orsmaller distance than the rail guides of the cover coupled to thesub-node chassis installed at 1002. In this way, the additional sub-nodechassis installed at 1004 may be positioned at a higher or lowerelevation in the server system chassis than the sub-node chassisinstalled at 1002. Additionally subsequent sub-node chassis installed inthe server system chassis may be coupled with covers that include railguides that extend away from the respective covers by incrementallygreater or smaller distances. Thus, when multiple sub-node chassis areinstalled in a server system chassis via a common rail each sub-nodechassis may be position at a slightly higher or lower elevation than asub-node chassis adjacent to the sub-node chassis. In some embodiments,multiple sub-node chassis of a server node may be arranged in a stairstep arrangement such that a volume of space above the multiple sub-nodechassis increases or decreases along a depth of the server systemchassis and a volume of space below the multiple sub-node chassisincreases or decreases a corresponding amount along the depth of theserver system chassis.

At 1006, an intra node connector of the additional sub-node chassis iscaused to couple with an intra-node connector of a sub-node chassis thatwas previously installed in the server system chassis. In someembodiments, intra node connectors may be blind mate connectors, so thatas one sub-node chassis is slid along a rail of a server system chassisan intra node connector of the sub-node chassis engages with acorresponding intra node connector of an adjacent sub-node chassisinstalled on the rail. In some embodiments, sliding a sub-node chassisinto a server system chassis without a rail or rail guides may cause anintra node connector of the sub-node chassis to engage with and couplewith an intra node connector of an adjacent sub-node chassis mounted inthe server system chassis. In some embodiments, 1004 may be omittedbetween installing each sub-node chassis and may be performed after allor multiple sub-node chassis are installed in a server system chassis.For example, in some embodiments multiple sub-node chassis may beinstalled in a server system chassis and when a last sub-node chassis isinstalled in the server system chassis, a force may be applied to thelast sub-node chassis to cause multiple intra node connectors of themultiple sub-node chassis installed in the server system chassis for theserver node to couple together. In some embodiments, a server systemchassis may include power and/or network connectors that are blind mateconnectors, and at least one sub-node chassis may include correspondingpower and/or network blind mate connectors. In such embodiments, a forcemay be applied to a group of sub-node chassis installed in a serversystem chassis to cause the blind mate power and/or network connectorsof the at least one sub-node chassis to couple with blind mate powerand/or network connectors of the server system chassis.

At 1008, it is determined if there are additional sub-node chassis to beinstalled for the server node. In response to determining there areadditional sub-node chassis to be installed for the server node, theprocess reverts to 1004 and the next additional sub-node chassis isinstalled. If there are not additional sub-node chassis to be installedfor the server node, at 1010 it is determined if additional server nodesare to be installed in the server system chassis. In response todetermining additional server nodes are to be installed in the serversystem chassis, the process reverts to 1002 and the first sub-nodechassis of the next server node is installed in the server systemchassis.

In response to determining at 1010 that there are not additional servernodes to be installed in the server system chassis, at 1012 the serversystem that includes the server nodes comprising sub-node chassiscoupled together via intra node connectors is put into operation.

FIG. 11 illustrates a method of replacing a device mounted in a sub-nodechassis installed in a server system chassis, according to someembodiments. At 1102 a sub-node chassis of a server node is removed froma server system chassis. A server node may include multiple sub-nodechassis mounted in a server system chassis, so that in somecircumstances when a device in a sub-node chassis that is mounted in theserver system chassis behind one or more other sub-node chassis is to bereplaced, multiple sub-node chassis may be removed from the serversystem chassis to reach the sub-node chassis that includes the devicethat is to be replaced. In some embodiments, a device may be removed,inspected and re-installed in a sub-node chassis without replacing thedevice in accordance with the method of FIG. 11. In some embodiments,each sub-node chassis including mass storage devices and server devicesmounted in the sub-node chassis may weigh less than 50 pounds. In someembodiments, a sub-node chassis may be configured such that a singleperson can safely lift the sub-node chassis into a server system chassismounted in a rack without help or risk of injury and remove the sub-nodechassis from a server system chassis mounted in the rack without help orrisk of injury.

At 1104 a cover of the sub-node chassis is removed from the sub-nodechassis to gain access to mass storage devices and/or server devicesmounted in the sub-node chassis. In some embodiments, a cover of asub-node chassis may be coupled to the sub-node chassis via a screw,pin, latch, or other suitable securing mechanism. In some embodiments,removing the cover from the sub-node chassis may include disengaging asecuring mechanism, such as a screw, pin, latch, etc.

After the cover is removed from the sub-node chassis, at 1106, pressuremay applied to a bottom side of a mass storage device or a server devicemounted in the sub-node chassis to remove the mass storage device orserver device from the sub-node chassis. In some embodiments a sub-nodechassis may include one or more open corners through which the cornersand a portion of the bottom surface of the mass storage devices and/orserver devices are accessible. Pressure may be applied to the massstorage devices and/or server devices via the open corners from anoutside side of the sub-node chassis.

At 1108, a new mass storage device or server device is installed in thesub-node chassis. In some embodiments, the same mass storage device orserver device may be re-installed in the sub-node chassis. In someembodiments, a mass storage device may be replaced with a server device,or a server device may be replaced with a mass storage device in orderto alter storage capabilities or compute capabilities of the servernode.

At 1110, the cover is re-attached to the sub-node chassis. A cover maybe re-attached or re-coupled to a server node chassis by re-engaging asecuring mechanism such as a screw, pin, fastener, etc.

At 1112, the sub-node chassis is reinstalled in the server systemchassis. In some embodiments, re-installing the sub-node chassis in theserver system chassis may include sliding rail guides of a cover coupledto the sub-node chassis onto rails mounted on the server system chassis.In some embodiments, a sub-node chassis may include legs and feet thatslide on a bottom surface of a server system chassis without using railsand rail guides. In some embodiments a sub-node chassis may be supportedin a server system chassis via other suitable structures.

At 1114, an intra-node connector coupled to the sub-node chassis iscaused to couple with an intra-node connector of an adjacent sub-nodechassis. In some embodiments, an intra node connector may be a blindmate connector such that sliding a sub-node chassis into position andapplying a threshold amount of force to the sub-node chassis causes theintra node connector of the sub-node chassis to couple with an intranode connector of an adjacent sub-node chassis. In some circumstances inwhich multiple sub-node chassis were removed to reach the mass storagedevice or server device that was to be replaced, 1112 and 1114 may berepeated for each sub-node chassis that was removed from the serversystem chassis.

In some embodiments, mass storage devices in a server system arestandard, off-the-shelf hard disk drives. Examples of suitable hard diskdrive form factors may include 3.5″, 5.25″, and 2.5″. In one embodiment,a standard 3.5″ hard disk drive is installed in a sub-node chassis of aserver node with other standard 3.5″ hard disk drives. In someembodiments, a server device installed in a sub-node chassis may have aform factor equivalent to a 2.5″, 3″, 3.5″, or 5.25″ hard disk drive.

Although in the embodiments described above, some of the server systemshave been described as being 3 U, 4 U, or 5 U in height, server systemsmay in various embodiments be 2 U, 4 U, 5 U, 6 U or any other height ordimensions.

The various methods as illustrated in the figures and described hereinrepresent example embodiments of methods. The order of method may bechanged, and various elements may be added, reordered, combined,omitted, modified, etc.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A device, comprising: a server node configured tomount in a server system chassis, wherein the server node comprises: aplurality of sub-node chassis; and a plurality of backplanes, whereinrespective backplanes of the plurality of backplanes are mounted inrespective sub-node chassis of the plurality of sub-node chassis,wherein the server system chassis is configured to mount in a rack;wherein each sub-node chassis is configured to be individually installedin the server system chassis when the server system chassis is mountedin the rack; and wherein each respective backplane mounted in arespective sub-node chassis is configured to allow communication betweenmass storage devices or server devices mounted in the respectivesub-node chassis and mass storage devices or server devices mounted inanother one of the sub-node chassis of the server node via one or moreintra node connections between the respective backplane and a backplanemounted in the other sub-node chassis formed due to installation of therespective sub-node chassis or the other sub-node chassis.
 2. The deviceof claim 1, further comprising: one or more intra node connectorscoupled to the respective backplanes, wherein the one or more intra-nodeconnectors are configured to couple with corresponding intra nodeconnectors of one or more adjacent sub-node chassis to form the one ormore intra node connections.
 3. The device of claim 1, furthercomprising mass storage devices or server devices mounted in therespective ones of the sub-node chassis, wherein each of the sub-nodechassis including the mass storage devices or server devices areconfigured to be manually lifted into and out of the server systemchassis by a single person, when the server system chassis is mounted inthe rack.
 4. The device of claim 1, wherein respective ones of thesub-node chassis are positioned in the server system chassis such thatan air space through the server system chassis is formed above or belowadjacent ones of the respective sub-node chassis.
 5. The device of claim4, wherein each of the sub-node chassis of the server node comprise legsconfigured to elevate a body of the respective sub-node chassis above asurface of the server system chassis, wherein the respective ones of themultiple sub-node chassis of the server node comprise legs of differentlengths such that the respective ones of the sub-node chassis of theserver node are positioned at different elevations in the server systemchassis.
 6. The device of claim 4, wherein each of the sub-node chassisof the server node comprises a cover comprising rail guides mounted onthe cover, wherein separate respective ones of the rail guides extendaway from respective separate ones of the sub-node chassis covers bydifferent respective distances such that the respective separate ones ofthe sub-node chassis are positioned at different elevations in theserver system chassis.
 7. The device of claim 1, further comprising aserver device, wherein components of the server device are integratedinto one of the backplanes.
 8. The device of claim 1: wherein a givensub-node chassis of the plurality of sub-node chassis is configured tobe removed from the server system chassis mounted in the rack, whereinthe given sub-node chassis comprises a portion of an array of massstorage devices of the server node, and wherein the given sub-nodechassis is configured to be individually removed from the server systemchassis mounted in the rack while other sub-nodes of the server noderemain in the server system chassis mounted in the rack.
 9. The deviceof claim 8, further comprising: a cover of the given sub-node chassisconfigured to be removed to gain access to mass storage devices mountedin the removed sub-node chassis, wherein the cover comprises rail guidesmounted on the cover, wherein the rail guides are configured to slide onrails mounted on the server system chassis.
 10. The device of claim 8,wherein: the given sub-node chassis is configured for a mass storagedevice to be removed from the given sub-node chassis via an open cornerof the given sub-node chassis in response to pressure applied to themass storage device.
 11. The device of claim 8, wherein: the givensub-node chassis is configured to be re-installed in the server systemchassis mounted in the rack subsequent to removal; and an additionalsub-node chassis is configured to be installed in the server systemchassis mounted in the rack and couple with the re-installed sub-nodechassis via one or more intra-node connectors.
 12. The device of claim11, further comprising: feet of the sub-node chassis configured to slideon a bottom surface of the server system chassis to position the givensub-node chassis in the server system chassis when being re-installed.13. The device of claim 11, wherein the given sub-node chassis has a tubconfiguration including: a tub configured to slide on a bottom surfaceof the server system chassis to position the sub-node chassis in theserver system chassis when being re-installed, wherein the tub comprisesmass storage devices or server devices mounted at different elevationsabove a bottom surface of the server system chassis when mounted in theserver system chassis.
 14. A server system comprising: a plurality ofserver nodes, each server node comprising: a plurality of sub-nodechassis configured to be individually inserted into a server systemchassis mounted in a rack and removed from the server system chassismounted in the rack, wherein each sub-node chassis comprises an intranode connector configured to engage with an intra node connector of anadjacent sub-node chassis to allow communications between a sub-nodecomprising the sub-node chassis and an adjacent sub-node of the servernode, and wherein respective ones of the sub-node chassis are positionedin the server system chassis such that an air space through the serversystem chassis is formed above or below adjacent ones of the respectivesub-node chassis.
 15. The server system of claim 14, wherein each of thesub-node chassis further comprise a backplane mounted in the sub-nodechassis, wherein the intra node connector of the respective sub-nodechassis is coupled to the backplane.
 16. The server system of claim 15,wherein each of the backplanes further comprises one or more openingsthat permit airflow through the respective backplane.
 17. The serversystem of claim 14, wherein the air space above or below adjacent onesof the respective sub-node chassis increases across a respective servernode and another air space above or below the adjacent ones of therespective sub-node chassis decreases across the respective server node.18. The server system of claim 17, wherein the air space or the otherair space forms a cold air plenum through which cool air is supplied tomass storage devices or server devices mounted in the respectivesub-node chassis, and wherein a different one of the air space or theother air space forms a warm air plenum through which air that hascooled the mass storage devices or the server devices flows away fromthe mass storage devices or the server devices.
 19. The server system ofclaim 14, further comprising a server device and one or more massstorage devices mounted in one of the sub-node chassis, wherein theserver device occupies up to an equivalent volume of space in thesub-node chassis as one of the mass storage devices mounted in thesub-node chassis.
 20. The server system of claim 14, wherein at leasttwo of the sub-node chassis are mounted in the server system adjacent toone another, wherein the intra node connectors of the at least twosub-node chassis are mounted on adjacent sides of the sub-node chassis.